# Polyethersulfone (PES)

PES is a thermoplastic, further classified as a sulfone plastic. It has a moderately high ductility and a moderately high tensile strength relative to other thermoplastics. The graph bars on the material properties cards below compare PES to: sulfone plastics (top), all thermoplastics (middle), and the entire database (bottom). The length of each bar shows the given value as a % of the largest value in the relevant set.

## Mechanical Properties

Elastic (Young's, Tensile) Modulus

2.6 *GPa* 0.38 *x 10 ^{6} psi*

Elongation at Break

65 *%*

Flexural Modulus

2.6 *GPa* 0.38 *x 10 ^{6} psi*

Flexural Strength

130 *MPa* 18 *x 10 ^{3} psi*

Impact Strength: Notched Izod

91 *J/m* 1.7 *ft-lb/in*

Rockwell M Hardness

88

Tensile Strength: Ultimate (UTS)

87 *MPa* 13 *x 10 ^{3} psi*

## Thermal Properties

Glass Transition Temperature

220 *°C* 430 *°F*

Heat Deflection Temperature At 1.82 MPa (264 psi)

200 *°C* 390 *°F*

Heat Deflection Temperature At 455 kPa (66 psi)

210 *°C* 410 *°F*

Specific Heat Capacity

1100 *J/kg-K* 0.26 *BTU/lb-°F*

Thermal Conductivity

0.18 *W/m-K* 0.1 *BTU/h-ft-°F*

Thermal Expansion

53 *µm/m-K*

## Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 Hz

3.5

Dielectric Constant (Relative Permittivity) At 1 MHz

3.5

Dielectric Strength (Breakdown Potential)

16 *kV/mm* 0.63 *V/mil*

Electrical Dissipation At 1 Hz

0.0010

Electrical Dissipation At 1 MHz

0.0035

Electrical Resistivity Order of Magnitude

15 *10 ^{x} Ω-m*

## Otherwise Unclassified Properties

Density

1.4 *g/cm ^{3}* 86

*lb/ft*

^{3}Limiting Oxygen Index (LOI)

36 *%*

Water Absorption After 24 Hours

0.34 *%*

## Common Calculations

Stiffness to Weight: Axial

1.1 *points*

Stiffness to Weight: Bending

33 *points*

Strength to Weight: Axial

18 *points*

Strength to Weight: Bending

32 *points*

Thermal Diffusivity

0.12 *m ^{2}/s*

Thermal Shock Resistance

45 *points*

## Followup Questions

## Further Reading

SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc., 5th ed., Michael L. Berins (editor), 2000

Modern Plastics Handbook, Charles A. Harper (editor), 1999

Plastics Materials, 7th ed., J. A. Brydson, 1999